Power Button not working - Coolpad Cool 1

Power button of My Cool1 phone is not working for the last 2 months. All these days i kept the phone on by charging the phone frequently. (Also i have used the settings Scheduled power On also).

My bad time 4 days back i have missed to charge it and the phone got switched off in night. I charged and waited for the scheduled time to get it on. But it is not getting back to life. (Yesterday My Brother told that he was playing games in this mobile and turned off the Scheduled ON option 10 days back itself ).

Now how to switch on without power button. All other keys are working.

info 1. When i connect the usb, phone is getting charged and showing 100 % in green (both in charger or connected to a desktop).
info 2. When i long press the volume up button and connect the usb cable in cpu, then in phone it is going to a screen showing ‘Download and install a package’. Again i pressed volume up button, the next screen shows ‘You have entered fastboot mode. Pls long press the power key to exit and boot normally’. But in my case power button not working, so stuck at this place.
info 3. Already downloaded Android Studio and Minimal ADB and Fastboot and tried, but i dont know how to use these tools.

Anyone pls help me to switch on my phone?

@getready @androgame